class PerSon{
    // TS 中必须声明 需要指令类型
    name:string
    age:number = 10;
    // 声明好属性之后 属性必须赋一个默认值 或者在构造函数中进行初始化
    constructor(name:string,age:number){
        this.name = name;
        this.age = age
    }

    sayHollow(msg:string):string{ //返回字符串
        console.log(msg);
        return msg
    }
    sayHollow1(msg:string):void{ //没有返回值
        console.log(msg);
    }
}